import socket
import struct
def get_tcp_data(packet_data):
    #判断帧头是否符合卓研
    if packet_data[:4].decode('ascii') == '####':
        print("开始解析报文帧")
        packet_type = struct.unpack('>I', packet_data[4:8])[0]  #获取报文类型 7为gps， 12为ais
        packet_lenth = struct.unpack('>I', packet_data[8:12])[0]
        packet_content = packet_data[12:]
        if packet_type == 7:
            print(f"GPS内容长度: {packet_lenth} 字节")
            data = get_gps_data(packet_content)
            print(data)
        elif packet_type == 12:
            print(f"AIS内容长度: {packet_lenth} 字节")
            data = get_ais_data(packet_content)
            print(data)

def get_gps_data(packet_content):
    fields = struct.unpack('>QiiiHHHBBIII', packet_content)
    res = {}
    res['utc_time'] = fields[0]        # UTC时间 (8字节)
    res['longitude'] = fields[1]/10000000      # 经度 (4字节，东经120.5度)
    res['latitude'] = fields[2]/10000000        # 纬度 (4字节，北纬30.5度)
    res['altitude'] = fields[3]                # 海拔高度 (4字节，50米)
    res['used_sats'] = fields[4]               # 定位使用的卫星数 (2字节)
    res['gps_sats'] = fields[5]                 # GPS卫星数 (2字节)
    res['beidou_sats'] = fields[6]              # 北斗卫星数 (2字节)
    res['gps_status'] = fields[7]               # GPS状态 (1字节，单点定位)
    res['position_mode'] = fields[8]           # 定位模式 (1字节，3D定位)
    res['hdop'] = fields[9]/10                 # 水平精度因子 (4字节，25.5米)
    res['speed'] = fields[10]/100                # 运动速度 (4字节，10.24节)
    res['direction'] = fields[11]             # 运动方向 (4字节，359度)
    return res

def get_ais_data(packet_content):
    res ={}
    demod_packet = packet_content[:9]
    demod_data = packet_content[9:]
    fields = struct.unpack('>BBBHHH', demod_packet)
    res['message_type'] = fields[0]
    res['satellite_id'] = fields[1]
    res['demodulator_id'] = fields[2]
    res['demod_slot'] = fields[3]
    res['receive_delay'] = fields[4]
    snr_packed = fields[5]
    # 解析SNR
    snr_int = (snr_packed >> 8) & 0xFF
    snr_frac = snr_packed & 0xFF
    res['snr'] = snr_int + snr_frac / 100.0
    print(demod_data)
    res['demod_data'] = get_demod_data(demod_data)
    return res

def get_demod_data(bit_string):
    # 如果输入是字节类型，先转换为二进制字符串
    if isinstance(bit_string, bytes):
        bit_string = ''.join(format(byte, '08b') for byte in bit_string)
    pos = 0
    decoded = {}
    
    decoded['message_id'] = int(bit_string[pos:pos+6], 2)   # 消息ID (6 bits)
    pos += 6 
    decoded['repeat_indicator'] = int(bit_string[pos:pos+2], 2)    # 转发指示符 (2 bits)
    pos += 2
    decoded['user_id'] = int(bit_string[pos:pos+30], 2)         # 用户ID/MMSI (30 bits)
    pos += 30
    decoded['navigation_status'] = int(bit_string[pos:pos+4], 2)        # 导航状态 (4 bits)
    pos += 4
    
    # 旋转速率 (8位有符号整数)
    rot_value = int(bit_string[pos:pos+8], 2)
    if rot_value > 127:
        rot_value -= 256
    decoded['rot'] = rot_value
    pos += 8
    
    decoded['sog'] = int(bit_string[pos:pos+10], 2)                 # 地面航速 (10 bits)
    pos += 10
    decoded['position_accuracy'] = int(bit_string[pos], 2)        # 位置准确度 (1 bit)
    pos += 1
    
    # 经度 (28位)
    longitude_value = int(bit_string[pos:pos+28], 2)
    decoded['longitude'] = longitude_value / (60 * 10000)  # 转换为度
    pos += 28
    
    # 纬度 (27位)
    latitude_value = int(bit_string[pos:pos+27], 2)
    decoded['latitude'] = latitude_value / (60 * 10000)  # 转换为度
    pos += 27
    
    decoded['cog'] = int(bit_string[pos:pos+12], 2)         # 地面航线 (12 bits)
    pos += 12
    decoded['true_heading'] = int(bit_string[pos:pos+9], 2)          # 实际航向 (9 bits)
    pos += 9
    decoded['timestamp'] = int(bit_string[pos:pos+6], 2)              # 时戳 (6 bits)
    pos += 6
    decoded['special_maneuver'] = int(bit_string[pos:pos+2], 2)         # 特定操纵指示符 (2 bits)
    pos += 2
    decoded['spare'] = int(bit_string[pos:pos+3], 2)                   # 备用 (3 bits)
    pos += 3
    decoded['raim_flag'] = int(bit_string[pos], 2)               # RAIM标志 (1 bit)
    pos += 1
    decoded['comm_state'] = int(bit_string[pos:pos+19], 2)              # 通信状态 (19 bits)

    return decoded

def receive_data():
    """接收数据"""
    host = 'localhost'
    port = 8082
    
    with socket.socket(socket.AF_INET, socket.SOCK_DGRAM) as s:
        s.bind((host, port))
        print(f"监听 {host}:{port}...")
        
        while True:
            try:
                data, addr = s.recvfrom(4096)  # 接收缓冲区大小
                print(f"\n收到来自 {addr} 的数据:")
                print("原始数据(十六进制):", data.hex())
                get_tcp_data(data)

                
            except KeyboardInterrupt:
                print("\n停止接收")
                break
            except Exception as e:
                print(f"接收错误: {e}")
                break

if __name__ == "__main__":
    receive_data()